The present invention relates to an arrangement for driving out of volatile impurities from ground water and a ground region through which the ground water passes. More particularly, it relates to such an arrangement of the above mentioned type, in which the volatile impurities are driven out by producing a negative pressure in a well shaft extending in the region of the contaminated ground water, and also by supply of a gas, particularly air, through a nozzle member in the ground water in the well shaft.
Arrangements of the above mentioned general type are known in the art. One of such arrangements is disclosed for example in the German document DE-OS 3,625,488. In this arrangement air or gas is supplied under the action of the negative pressure produced in the well shaft through a conduit into an air receiving chamber under the ground water level in the well shaft. The air receiving chamber is separated by a nozzle plate from a water chamber, and the nozzle plate is suspended on a float in an adjustable distance underneath the water surface. The arrangement has been proven extraordinarily successful in practice. However, in the event of very narrow diameters of the shaft difficulties arise in mounting of the float and the nozzle plate.